Methods and apparatus for automation of the testing and measurement of optical fiber

ABSTRACT

A system and methods for automating the testing of optical fiber are described. According to one aspect of the present invention, an automated conveyor system moves spools of optical fiber contained on pallets from testing station to testing station. According to another aspect of the present invention, a single spool is carried by a specially designed pallet. According to another aspect of present invention, an apparatus automatically strips, cleans, and cleaves the fiber ends once the spool reaches the apparatus. The fiber ends are then automatically manipulated into the appropriate location for a predetermined test to be performed. According to another aspect of the invention, an apparatus automatically acquires a sample length of the optical fiber and strips, cleans, and cleaves the fiber ends of the sample. The sample length of the optical fiber is then manipulated into the appropriate location for a second predetermined test to be performed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is application claims the benefit of U.S. Provisional PatentApplication Ser. No. 60/166,015 filed on Nov. 17, 1999 and U.S.Provisional Patent Application Ser. No. 60/168,111 filed on Nov. 30,1999, the content of which is relied upon and incorporated herein byreference in its entirety, and the benefit of priority under 35 U.S.C. §120 is hereby claimed.

FIELD OF THE INVENTION

The present invention relates generally to improvements in themanufacture of optical fiber. More specifically, the present inventionrelates to methods and apparatus for automating the testing of opticalfiber wound onto a spool.

BACKGROUND OF THE INVENTION

In the current manufacturing process for optical fiber, optical fiber istypically wound onto a spool for measurement and testing, shipping to acustomer, and subsequent processing at the customer's facility. Themeasurement and testing of optical fiber is currently performed manuallyby multiple technicians, with carts carrying a number of spools beingmanually moved from test station to test station. At a test station atechnician removes a spool from the cart and places the spool on ameasurement rack. The technician then strips and removes the plasticfiber coating from both ends of the optical fiber, cleaning off excesscoating and any remaining debris. The fiber ends are manipulated by thetechnician into a cleaver and cut. Next, the technician loads the fiberends into a computer controlled measurement system and initiates ameasurement sequence to test at least one characteristic of the opticalfiber, e.g., fiber cutoff wavelength, attenuation, fiber curl, claddingdiameter, or coating diameter. The fiber is then removed from thetesting system and the spool returned to the cart. All of the spools onthe cart or only selected spools may be tested as desired. The cart isthen manually moved to the next test station for another series oftests. The amount of manual labor involved results in high labor costsand higher manufacturing costs for optical fiber.

Accordingly, it would be highly advantageous to further automate themanual steps of optical fiber measurement and testing, reducing the timerequired in the measurement and testing area and thus reducing the costof manufacturing optical fiber and providing faster feedback on themanufacturing process. Additionally, it would be highly advantageous toprovide methods and apparatus for the automated testing of optical fiberwhich reduces the opportunity for human error and provides a morerepeatable process.

SUMMARY OF THE INVENTION

The present invention provides advantageous methods and apparatus forthe automation of the testing of optical fiber. The present inventionincludes an automated conveyor system which moves spools of opticalfiber contained on pallets from testing station to testing station.According to one aspect of the present invention, a single spool iscarried by a specially designed pallet which has a number ofadvantageous features described further below. According to anotheraspect of present invention, an apparatus automatically strips, cleans,and cleaves the fiber ends once the spool reaches the apparatus. Thefiber ends are then automatically manipulated into the appropriatelocation for a predetermined test to be performed. According to anotheraspect of the invention, an apparatus automatically acquires a samplelength of the optical fiber and strips, cleans, and cleaves the fiberends of the sample. The sample length of the optical fiber is thenmanipulated into the appropriate location for a second predeterminedtest to be performed.

These and other features, aspects and advantages of the invention willbe apparent to those skilled in the art from the following detaileddescription taken together with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a view of a spool which may suitably be used in conjunctionwith the present invention;

FIG. 2 shows an isometric view of a pallet in accordance with thepresent invention;

FIGS. 3A, 3B, 3C, and 3D show, respectively, top, front, side, andisometric views of a pallet in accordance with the present invention;

FIG. 4 shows an isometric view of the pallet of FIG. 2 carrying thespool of FIG. 1;

FIG. 5 shows an isometric view of a pallet in accordance with anotheraspect of the present invention carrying the spool of FIG. 1;

FIGS. 6A, 6B, 6C, and 6D show, respectively, top, front, side, andisometric views of the pallet of FIG. 5;

FIG. 7 shows an isometric view of the pallet of FIG. 5 carrying thespool of FIG. 1.

FIG. 8 is an overall view of an automated optical fiber testing systemin accordance with the present invention;

FIG. 9 shows a detailed view of a preparation station suitable for usein conjunction with the system of FIG. 8;

FIG. 10A shows a detailed view of an optical time domain reflectrometryand optical dispersion test station suitable for use in conjunction withthe system of FIG. 8;

FIG. 10B is a flowchart of a method for automating the performance ofthe optical time domain reflectrometry and the optical dispersion testsof FIG. 10A in accordance with the present invention;

FIG. 11A shows a detailed view of a glass measurement and cutoffwavelength test station suitable for use in conjunction with the systemof FIG. 8;

FIGS. 11B and 11C are a flowchart of a method for automating theperformance of the glass measurement and cutoff frequency tests of FIG.11A in accordance with the present invention;

FIG. 12A shows a detailed view of a fiber deflection test station andcoating geometry test station suitable for use in conjunction with thesystem of FIG. 8;

FIG. 12B is a flowchart of a method for automating the performance ofthe optical fiber deflection and coating geometry tests of FIG. 12A inaccordance with the present invention;

FIG. 13A shows a detailed view of a polarization modal dispersion teststation suitable for use in conjunction with the system of FIG. 8;

FIGS. 13B and 13C are a flowchart of a method for automating theperformance of the polarization modal dispersion test of FIG. 13A inaccordance with the present invention; and

FIG. 14 shows a detailed view of an unload station suitable for use inconjunction with the system of FIG. 8.

DETAILED DESCRIPTION

The present invention now will be described more fully with reference tothe accompanying drawings, in which several currently preferredembodiments of the invention are shown. However, this invention may beembodied in various forms and should not be construed as limited to theexemplary embodiments set forth herein. Rather, these representativeembodiments are described in detail so that this disclosure will bethorough and complete, and will fully convey the scope, structure,operation, functionality, and potential of applicability of theinvention to those skilled in the art.

Referring to the drawings, FIG. 1 shows a top view of a spool 10 whichmay be advantageously used in conjunction with the present invention.The spool 10 comprises a primary barrel 14 and a lead meter barrel 15separated from each other by an outboard flange 16. A length of opticalfiber 12 has been wound onto the primary barrel 14 and the lead meterbarrel 15 during the manufacturing process. In a presently preferredembodiment, spool 10 may be, for example, a “single” spool, having 25 kmof optical fiber wound onto the primary barrel 14, or a “double” spoolcontaining 50 km of optical fiber wound onto the primary barrel 14. Ashort length of the optical fiber 12 has been wound onto the lead meterbarrel 15. The outboard flange 16 has a slot 17 providing a path for theoptical fiber 12 between the lead meter barrel 15 and the primary barrel14. As seen from the top view of FIG. 1, an outer end 12 a of theoptical fiber 12 extends from the underside of the primary barrel 14 andan inner end 12 b extends from the underside of the lead meter barrel15. The optical fiber 12 also typically includes a plastic coating 13.Further details of a presently preferred spool 10 for use in conjunctionwith the present invention are provided in U.S. patent application Ser.No. 60/115,540, filed on Jan. 12, 1999, entitled “System And Methods ForProviding Under-Wrap Access To Optical Fiber Wound Onto Spools” whichcorresponds to PCT Application No. WO 00/40495, filed Dec. 14, 1999,which is incorporated by reference herein in its entirety.

FIG. 2 shows an isometric view of a pallet 50 in accordance with a firstembodiment of the present invention. The pallet 50 is adapted to carrythe spool 10 of optical fiber 12 such that the fiber ends 12 a and 12 bare available to the testing equipment of automated fiber measurementsystem 100 described below. The pallet 50 includes a roller assembly 52mounted on a base 54 adapted for carrying the spool 10. The rollerassembly 52 includes a pair of rollers 56 and a pair of base plates 58.Also mounted on the base 54 are vertical brackets 60 and 62, and anupright guide roller 64. As shown in FIGS. 3A and 3C, a guide bar 66 ismounted to the base 54. A feed finger assembly 68, a pickoff assembly70, and a clutch assembly 71 are rotationally mounted on the verticalbracket 60. Mounted to the pickoff assembly 70 is a fiber guide 72 whichincludes an eyelet 74. A feed finger assembly 76, a guide roller 80, anda fiberguide 81 including an eyelet 83 are mounted on the verticalbracket 62. As best seen in FIG. 4, a center hole 84 extends through therotational center of the feed finger assembly 68, the pickoff assembly70, and the vertical bracket 60.

As shown in FIG. 3D, a radio frequency (RF) identification tag 82identifying the spool 10 is attached to the vertical bracket 60. Inaddition to identifying the spool 10, the RF tag 82 is capable ofstoring information which has been written to it, allowing the RF tag 82to provide a travelling database for the spool 10 as it passes throughthe system 100. The RF tag 82 provides processing instructions forindividual test stations and stores the data of the test results. Aseach spool 10 is processed by the individual test stations of the system100, the results of each of the tests are written to the RF tag 82.Thus, when the spool 10 has been processed by each of the appropriatetest stations, the RF tag 82 contains the test results of all the testsperformed. Additionally, the RF tag 82 also contains the routinginstructions for the spool 10, indicating which test stations need toprocess the spool 10.

FIG. 4 shows a view of the pallet 50 carrying the spool 10. To load thespool 10 onto the pallet 50, an operator manually places the spool 10 onthe rollers 56 and feeds the inner end 12 b of the optical fiber fromlead meter barrel 15 through the eyelet 74, center hole 84 and feedfinger assembly 68 such that the end 12 b extends outward from the feedfinger assembly 68. The outer end 12 a of the optical fiber from primarybarrel 14 is first fed around the guide roller 64, over guide roller 80,and then fed through the eyelet 83 and feed finger assembly 76 such thatthe outer end 12 a extends outward from the feed finger assembly 76.Thus, as shown in FIG. 4, the pallet 50 provides convenient access tothe ends 12 a and 12 b of the optical fiber for both automated andmanual test equipment.

Furthermore, the spool 10 and pallet 50 advantageously allow the opticalfiber 12 to be unwound from either the inner end 12 b or the outer end12 a individually, or both the inner end 12 b and outer end 12 asimultaneously, without causing the opposite end to be disturbed. Thisallows both automated and manual test equipment to readily acquiresamples of optical fiber from either or both of the fiber ends 12 a and12 b. The fiber ends 12 a and 12 b may also be readily engaged andpulled or directed to test stations, allowing the optical fiber 12 to betested while wound onto the spool 10.

The clutch mechanism 71 includes at least a single wheel 150 that isforced into contact with the spool 10. The wheel 150 on clutch mechanism71 rotates in a single direction which enables fiber to be pulled fromfiber end 12 b, in this case the direction indicated by arrow 151. Asoptical fiber 12 is unwound from the outer end 12 a, the spool 10rotates in a counter-clockwise direction (as indicated by arrow 85 inFIG. 4), dispensing the optical fiber 12. Because the wheel 150 ofclutch assembly 71 does not rotate in a direction which is counter tothe direction indicated by arrow 151, the force caused by thecounterclockwise rotation of spool 10 causes the entire clutch assembly71, pickoff assembly 70, and feed finger assembly 68 to rotatecounter-clockwise around the axis of center hole 84 of feed fingerassembly 68. This rotation keeps the inner end 12 b of optical fiber 12from being removed from the spool 10. As the outer end 12 a of opticalfiber 12 is unwound from the spool, the tension on the inner end 12 b ofthe optical fiber 12 held by the fiber guide eyelet 74 exerts acounter-clockwise force on the fiber guide 74, causing the clutchassembly 71, the pickoff assembly 70, and the feed finger assembly 68 torotate in synchronization with the spool 10. In other words, as thespool 10 is rotated counter-clockwise by optical fiber 12 being unwoundfrom the outer end 12 a, the optical fiber 12 extending from the spool10 through the eyelet 74 of fiber guide 72 pulls the clutch assembly 71,the pickoff assembly 70, and the feed finger assembly 68 along with therotating spool 10.

As optical fiber 12 is unwound from the inner end 12 b, the clutchassembly 71, the pickoff assembly 70 and the feed finger assembly 68rotate counter-clockwise (as indicated by the arrow 85), causing wheel150 to rotate in the direction indicated by arrow 151, to thereby removeoptical fiber 12 from the lead meter barrel 15 while the spool 10remains fixed, preventing optical fiber 12 from unwinding from the spool10 on the outer end 12 a. The weight of the spool 10 prevents the spool10 from rotating as the fiber 12 is unwound from the inner end 12 b. Thetension caused by the optical fiber 12 being pulled through fiber guideeyelet 74 exerts a counter-clockwise force on fiber guide 72, and thusclutch assembly 71, the pickoff assembly 70, and the feed fingerassembly 68, causing these elements to rotate in a counterclockwisedirection as the optical fiber 12 is pulled through the feed fingerassembly 68.

Alternatively, fiber can be removed from spool 10 simultaneously bysimply pulling on both ends of fiber at the same time.

FIG. 5 shows an isometric view of a pallet 90 in accordance with asecond embodiment of the present invention. Since many components arearranged in the same manner as the first embodiment, like referencenumerals are used to designate elements common to the two embodiments.The pallet 90 is adapted to carry the spool 10 of optical fiber 12 suchthat the fiber ends 12 a and 12 b are available to the testing equipmentof system 20 described above. The pallet 90 includes a roller assembly52 mounted on a base 54 adapted for carrying the spool 10. The rollerassembly 52 includes a pair of rollers 56 and a pair of base plates 58.Mounted on the base 54 are vertical brackets 60 and 62. As best seen inFIGS. 6A and 6C, a vertical bracket 92 is also mounted on the base 54.As shown in FIG. 5, a feed finger assembly 68, a pickoff assembly 70,and a clutch assembly 71 are rotationally mounted on the verticalbracket 60. Mounted to the pickoff assembly 70 is a fiber guide 72 whichincludes an eyelet 74. A feed finger assembly 76 and a fiber guide 81including an eyelet 83 are mounted on the vertical bracket 62. As bestseen in FIG. 6B, a fiber guide 94 including an eyelet 95 and a fiberguide 96 including an eyelet 97 are mounted on the vertical bracket 92.A center hole 84 extends through the rotational center of the feedfinger assembly 68, the pickoff assembly 70, and the vertical bracket60.

As shown in FIG. 6D, a radio frequency (RF) identification tag 82identifying the spool 10 is attached to the vertical bracket 60. Inaddition to identifying the spool 10, the RF tag 82 is capable ofstoring information which has been written to it, allowing the RF tag 82to provide a traveling database for the spool 10 as it passes throughthe system 20. The RF tag 82 provides processing instructions forindividual test stations and stores the data of the test results. Aseach spool 10 is processed by the individual test stations of the system20, the results of the tests are written to the RF tag 82. The RF tag 82also contains the routing instructions for the spool 10, indicatingwhich test stations need to process the spool 10.

FIG. 7 shows a view of the pallet 90 carrying the spool 10. To load thespool 10 onto the pallet 90, an operator manually places the spool 10 onthe rollers 56 and feeds the inner end 12 b of the optical fiber throughthe eyelet 74, center hole 84 and feed finger assembly 68 such that theend 12 b extends outward from the feed finger assembly 68. The outer end12 a of the optical fiber is fed through the eyelets 97, 95 and 83, inrespective order, and then fed through the feed finger assembly 76 suchthat the end 12 a extends outward from the feed finger assembly 76.Thus, as shown in FIGS. 5 and 7, the pallet 90 provides convenientaccess to the fiber ends 12 a and 12 b of the optical fiber for bothautomated and manual test equipment.

Furthermore, the spool 10 and pallet 90 advantageously allow the opticalfiber 12 to be unwound from either the inner end 12 b or the outer end12 a, or both the inner end 12 b and the outer end 12 a simultaneously,without causing the opposite end to be disturbed. As optical fiber isunwound from the outer end 12 a, the spool rotates in acounter-clockwise direction (as indicated by arrow 85 in FIG. 7),dispensing the optical fiber. While the spool is rotatingcounter-clockwise, the clutch assembly 71, the pickoff assembly 70 andthe feed finger assembly 68 also rotate counter-clockwise, preventingoptical fiber 12 from pulling out of the feed finger assembly 68. As theoptical fiber 12 is unwound from the outer end 12 a, the tension on theinner end 12 b of the optical fiber 12 held by the fiber guide 74 exertsa counter-clockwise force on the fiber guide 74, causing the clutchassembly 71, the pickoff assembly 70, and the feed finger assembly 68 torotate in synchronization with the spool 10. In other words, as thespool 10 is rotated counter-clockwise by optical fiber 12 being unwoundfrom the outer end 12 a, the optical fiber 12 extending from the spool10 through the fiber guide 74 pulls the clutch assembly 71, the pickoffassembly 70, and the feed finger assembly 68 along with the rotatingspool 10.

As optical fiber 12 is unwound from the inner end 12 b, the clutchassembly 71, the pickoff assembly 70 and the feed finger assembly 68rotate counter-clockwise to remove optical fiber 12 from the lead meterbarrel 15 while the spool 10 remains fixed, preventing optical fiber 12from unwinding from the spool 10 on the outer end 12 a. The tension onthe optical fiber 12 held by the fiber guide 74 exerts acounter-clockwise (as indicated by the arrow 85) force on the clutchassembly 71, the pickoff assembly 70, and the feed finger assembly 68,causing these elements to rotate counter-clockwise as the optical fiber12 is pulled through the feed finger assembly 68. The weight of thespool 10 prevents the spool 10 from rotating as the fiber 12 is unwoundfrom the inner end 12 b.

FIG. 8 shows an overall view of an automated optical fiber measurementsystem 100 in accordance with the present invention. The system 100 maysuitably include a load station 102 and an automated preparation station104 for preparing the two ends of a length of optical fiber while isstored on a fiber storage spool. Such a spool could be, for example, abulk storage spool or an actual fiber shipping spool. Shipping spool asused herein means a spool or reel containing a length of fiber and whichis to be shipped to a customer. The system 100 may also include anoptical time domain reflectrometer (OTDR) and optical dispersion teststation 106, a glass geometry measurement and fiber cutoff wavelengthtest station 108, a fiber deflection and optical fiber coating geometrytest station 110, a polarization modal dispersion (PMD) test station112, a visual inspection station 114, and an unload station 116. Whilepresently preferred optical fiber tests and test stations are disclosedherein, one skilled in the art will appreciate that the presentinvention may be utilized with fewer or additional tests and teststations, and should not be construed as limited to the tests and teststations shown and described herein. The automated measurement system100 includes a conveyor system 118 for transporting the pallets 50 or 90carrying spools 10 of optical fiber 12 from test station to teststation. A local programmable logic controller (PLC) 121 controls theoperation of the load station 102, the preparation stations 104, thevisual inspection station 114, and the unload station 116. As describedfurther below, additional local PLCs may be employed to control theoperation of the other stations. A plurality of RF devices, discussedfurther below, adapted to read from and/or write to the RF tag 82attached to the pallet 50 or 90, are located in a plurality of locationsadjacent to the conveyor system 118. Instructions read from the RF tag82 control the progress of the pallet 50 or 90 through the conveyorsystem 118 via the local PLCs.

To begin processing, the spool 10 is loaded onto the pallet 50 or 90with the fiber ends 12 a and 12 b positioned such they are readilyaccessible to the individual test stations of system 100, as describedabove. As shown in FIG. 8, the spool is loaded onto the pallet 50 or 90of the conveyor system 118 at the load station 102. The conveyor system118 then moves the pallet 50 or 90 to the preparation station 104.

As seen in FIG. 9, the preparation station 104 includes a strippingdevice 130 for stripping the protective coating off of the opticalfiber, and a cleaning device 132 for cleaning the fiber after the fibercoating has been stripped from the optical fiber. Both the strippingdevice and the cleaning device are preferably operated by pneumaticcontrol techniques, and preferably the operation of these devices isunder control of the local PLC 121 (shown in FIG. 8). Additionally, thePLC 121 controls the movement of the pallet 50 or 90 while the pallet 50or 90 is being processed by preparation station 104. After the PLC 121has positioned the pallet 50 or 90 such that the end 12 a is adjacent tothe device 130, the stripping device 130 operates by initially movingbelow the end 12 a and then rising up and positioning itself around end12 a. An auxiliary fiber clip (not shown) engages and securely holds theend 12 a between the striping device 130 and the pallet 50 or 90. Thestripping device 130 then closes around the end 12 a and retracts in adirection away from the pallet to remove the coating 13 from the end 12a The stripping device also includes a fiber cutting device capable ofperforming a rough cut on the fiber to achieve a desired length of fiberextending from the feed finger assemblies. For example, in oneembodiment, about 10 cm of fiber extends from the feed fingerassemblies, about 5 cm of which is fiber whose protective coating hasbeen removed. A vacuum nozzle then removes the coating debris into acentral vacuum system.

The fiber stripping devices employed herein to remove the protectivepolymeric can be conventional fiber stripping devices, for example suchas are available from the Miller Ripley Company, Miller Division,Cromwell, Conn., USA. Preferably the stripping devices employed hereinare connected to pneumatic valves which may be computer controlled tocontrol operation of the stripping devices. Fiber cutting can beachieved using conventional shears which are capable of performing arough cut on the fiber.

The pallet 50 or 90 is then moved forward so that end 12 a is adjacentto the cleaning device 132. The cleaning device 132 operates to removeany debris from the fiber end 12 a. The device 132 includes a cleaninghead, which may be, which includes a gripper mechanism having two armswith felt or sponge pads or alternatively, a polyurethane based opencell foam material. First, a needle squirts alcohol on to the pads tomoisten them. Then the gripper advances forward onto the fiber end 12 aand the alcohol dampened pads close onto the fiber end 12 a. The gripperthen pulls back away from the pallet 50 or 90, thereby cleaning thefiber end 12 a. Preferably, the gripper is then rotated 90 degrees andthe cleaning cycle is performed again.

The PLC 121 then positions the pallet 50 or 90 such that the end 12 b isadjacent to the stripping device 130. The stripping, cutting, andcleaning process is then repeated for the end 12 b. Alternatively, thecoating 13 could be removed and the optical fiber cleaned by manualtechniques. Preferably, the stripping and cutting device 130 and thecleaning device 132 are positioned so that, when one end of fiber isbeing stripped and cut to a desired length, the another end of fiber maybe being cleaned. The automatic stripping, cutting and cleaning stationis significant in that, for the first time, a fiber may be automaticallyprepared for testing, including removal of the protective polymericcoating and cutting of the end of the fiber, without any manualinteraction from an operator.

In the embodiment illustrated in FIG. 8, after an appropriate length ofeach fiber end 12A and 12 b has been stripped, cut, and cleaned, thepallet 50 or 90 is transported to test station 106. Alternatively,however, the pallet could be transported to an alternative test stationif desired. As shown in FIG. 10A, the OTDR and optical dispersion teststation 106 includes cutting devices 140, a cleaving device 142, fiberaligners 144, and fiber discarding devices 146. One fiber aligner 144suitable for use with the present invention is the Model 1100 SingleFiber Aligner (PK Technology Inc., Beaverton, Oreg. 97008). The teststation 106 includes an OTDR test machine 148 and an optical dispersiontest machine 150, both optically coupled to the fiber aligners 144 andcontrolled by one or more computers 154. The test station 106 alsoincludes a local PLC 152 communicatively connected to the computer 154,an RF tag reading device 160, and an RF tag writing device 162. A pairof fiber clips 156 are mounted on a servo slide 158 and controlled bythe local PLC 152. Operation of the test station 106, including thecomputer 154, is controlled by the local PLC 152. FIG. 10B illustratesaspects of a method 170 of automating the performance of the OTDR andoptical dispersion tests utilizing the test station 106 shown in FIG.10A. In a first step 171, the RF tag reading device 160 reads the RFidentification tag 52, determining routing instructions and processinginstructions for the spool 10. In a second step 172, the PLC determinesif the routing instructions indicate that the spool 10 should beprocessed by the test station 106. If the local PLC 152 determines thatthe spool is not to be processed by the test station 106, the pallet 50or 90 is moved to the next test station in step 173. If the local PLC152 determines the spool is to be processed by the test station 106, thepallet 50 or 90 is moved into position adjacent to the servo slide 158in step 174, as shown in FIG. 10A. Clips 156 are provided to grip theends of the fiber. Suitable clips for use as clips 156 can be so calledOptical Fiber Clips which are available from EG&G Fiber Optics,Wokingham, Berge, United Kingdom, or Optical Fiber Clips which are alsoavailable from PK Technologies Inc., Beaverton Oreg., USA. The fiberclips 156 preferably have a V-shaped groove therein parallel to thedirection the fiber will be inserted into the clip, and into which thefiber is grasped by the clip. The opening and closing of the clips ispreferably controlled using pneumatic control methods. The clips 156 aremoved by the servo slide 158 to the ends 12 a and 12 b where the clips156 engage and hold the optical fiber ends 12 a and 12 b. In step 175,the servo slide 158 moves the clips 156 holding the fiber ends to thecleaving device 142 where the fiber ends 12 a, 12 b may be cleaved, orprecision cut, leaving a predetermined length of optical fiber 12protruding from each clip 156. The cleaving device preferably is capableof cleaving the fiber in a manner which results in a cleaved surfacesuitable for optical coupling, for example to one of the testingapparatus described herein. Such cleaving can be accomplished usingoptical fiber cleaving devices such as are available from Seimens inGermany. These fiber cutting devices are preferably also adapted to becontrollable by pneumatic computer controlled devices. After an opticalquality cleave has been made, in step 176 the servo slide 158 moves theclips 156 toward the fiber aligners 144, inserting an appropriate lengthof the fiber ends 12 a, 12 b into the fiber aligners 144.

Next, in step 178, the computer 154 commands the OTDR test machine 148,which is optically connected to the fiber aligners 144 as describedabove, to test the optical fiber 12. The OTDR test machine 148 providesa measure of the fiber attenuation of the optical fiber 12 over aselected wavelength range. OTDR attenuation measurements are made at aplurality of wavelengths which are within a predetermined selectedrange. The measured attenuations are analyzed to produce a curverepresenting attenuation, i.e., spectral attenuation, for thewavelengths of the selected range.

Next, in step 180, the computer 154 commands the optical dispersion testmachine 150, which is also optically connected to the fiber aligners 144as described above, to test the optical fiber 12. The optical dispersiontest provides a measure of the distortion of optical signals as theypropagate down optical fiber 12. Next, in step 182, the fiber discardingdevices 146 engage and grasp the ends 12 a and 12 b of the opticalfiber, the cutting devices 156 cut the stripped ends 12 a and 12 b ofthe optical fiber 12, and the fiber discarding devices 146 remove thepieces of optical fiber which were severed from the testing area. Thefiber discarding devices 146 utilize a gripper mounted on a rod to gripthe severed pieces of optical fiber and move them into a scrap trough.Alternatively, the scrap fiber can be removed via a vacuum which ismounted or movable to a position which is close enough to remove thescrap fiber. Next, in step 184, the RF tag writing device 162 preferablywrites the results of the OTDR and optical dispersion tests to the RFidentification tag 52. The conveyor 118 then transports the pallet 50 or90 to the next test station.

As shown in FIG. 11A, the glass geometry measurement and cutoffwavelength test station 108 includes a fiber clip 200 attached to adeployment slide 202, a cutting device 204, and a fiber discardingdevice 206. The test station 108 also includes mandrels 208 a, 208 b,208 c, 208 d rotatably mounted on a dial plate 210. Mounted on eachmandrel 208 a, 208 b, 208 c, 208 d are fiber gripping clips 212, 213located at the ends of extension arms 215(a) and 215(b). A strippingdevice 214, a cleaning device 216, and cleaving device 218 are mountedon a slide 220. A cutoff wavelength tester 222 and a glass measurementtester 224 are communicatively connected to a vision alignment system226. The test station 108 also includes an RF tag reading device 232 andan RF tag writing device 234. Operation of the test station 108,including one or more computers 230, is controlled by a local PLC 228.

FIGS. 11B and 11C show a method 250 for automating the performance ofthe glass measurement and cutoff wavelength tests utilizing the teststation 108 shown in FIG. 11A. In a first step 251, the RF tag readingdevice 232 reads the RF identification tag 52, determining routinginstructions and processing instructions for the spool 10. In a secondstep 252, the local PLC 228 determines if the routing instructionsindicate that the spool 10 should be processed by the test station 108.If the local PLC 228 determines that the spool 10 is not to be processedby the test station 108, the pallet 50 or 90 is moved to the next teststation in step 253. If the local PLC 228 determines that the spool 10is to be processed by the test station 108, the pallet 50 or 90 is movedinto position adjacent to the slide 202 in step 254, as shown in FIG.11A. The fiber clip 200 is moved by the deployment slide toward thespool 10, where the fiber clip 200 engages and grabs the fiber end 12 a.The deployment slide 202 then moves the clip 200 away from the pallet 50or 90, deploying a length of the optical fiber 12. In step 255, thefiber clip 200 passes the fiber end 12 a to the fiber clip 212 mountedon the mandrel 208 a. During this step, the fiber clip 200 moveslaterally outward from slide 202 towards and into communication withclip 212 on mandrel extension arm 215(a). Next, in step 256, the mandrel208 a rotates counter-clockwise 1.5 rotations, wrapping approximatelytwo meters of optical fiber 12 around the mandrel 208 a, which isbasically a cylinder having a diameter of about 11 inches, or 280 cm.During this step, a fiber guide ensures proper containment of theoptical fiber 12 around mandrel 208(a) while the fiber is being woundonto the mandrel. Next, in step 258, the clip 213 attached to themandrel 208 a engages the optical fiber 12 and the cutting device 204performs a cut on the optical fiber 12, leaving about two inches offiber end exposed for testing. Thus, test station 108 has acquired asample length of the optical fiber 12 which is wrapped around themandrel 208 and held by the clips 212 and 213. Of course, this techniqueis not limited to use with an 11 inch diameter mandrel, and could beemployed instead on mandrels having a different diameter, e.g. 3 inches.

In step 260, the dial plate 210 rotates 90° counter-clockwise, bringingthe mandrel 208 a adjacent to the slide 220. In next step 262, the fiberends held by the clips 212, 213 are stripped of their plastic coating bystripping device 214, cleaned of excess debris by cleaning device 216,and cleaved by cleaving device 218, much the same as was described abovewith respect the stripping, cleaving, and cleaning station illustratedin FIG. 9. The stripping device 214, the cleaning device 216, and thecleaving device are movably mounted along the slide 220, and also areprovided with transverse slides (not shown) which enable movement ofthese devices transverse to slide 220 to facilitate the stripping,cutting, and cleaning operations to the ends 12 a and 12 b. After theseoperations, in step 264, the dial plate 210 rotates 90°counter-clockwise, bringing the mandrel to face the cutoff wavelengthtester 222, as illustrated by mandrel 208(c). Each of the rotatablemandrels are mounted on a slide located under the mandrel, which enablesmovement of the mandrel in the directions indicated by arrow 217. Tointerface the fiber ends 12 a and 12 b with cut-off tester 222, theentire mandrel 208(c) is moved towards cut-off tester to insert thefiber ends 12 a and 12 b into cut-off tester 222.

Next, in step 266, the PLC 228 commands the computer 230 to run thecutoff wavelength tester 222 to test the sample of optical fiber. Inthis step 266, the computer 230 directs the vision device 226 to alignthe lenses of the cutoff wavelength tester 222 with the fiber ends heldby the clips 212 and 213. The computer 230 then directs the cutoffwavelength tester 222 to test the sample of optical fiber. The cutoffwavelength test determines the cutoff wavelength at which the opticalfiber begins to operate like a single mode optical fiber.

Then, in step 268, the mandrel retracts back, pulling the fiber ends 12a and 12 b out of cut-off tester, and dial plate 210 rotates 90°counter-clockwise, bringing the mandrel 208 a adjacent to the glassmeasurement tester 224. In step 270, the PLC 228 commands the computer230 to test the sample of optical fiber. In this step 270, the visiondevice 226 aligns the lenses of the glass measurement tester 224 withthe fiber ends and the glass measurement tester 224 tests the opticalfiber. The glass measurement tester 224 determines relative geometricalparameters of the core and clad portions of the optical fiber sample.Additionally, the glass measurement tester 224 may measure the core andclad concentricity.

As shown in step 272, the dial plate 210 rotates 90° counter-clockwise,bringing the mandrel 208 a to face the pallet 50 or 90. Next, in step274, the fiber discarding device 206 grips one of the fiber ends, thefiber clips 212, 213 release the fiber ends, and the fiber discardingdevice 206 removes and discards the optical fiber sample. Next, in step276, the RF tag writing device 234 writes the results of cutoffwavelength and glass measurement tests to the RF identification tag 52.The conveyor 118 then transports the pallet 50 or 90 to the preparationstation 104 before passing the pallet 50 or 90 to the next test station.

The four mandrels 208 a, 208 b, 208 c, 208 d advantageously allow foursamples of optical fiber to be processed simultaneously, reducingequipment cost and improving throughput. While a first fiber sample isbeing acquired and wrapped around mandrel 208 a, a second fiber samplewrapped around mandrel 208 b may be being stripped, cleaned, andcleaved, a third fiber sample wrapped around mandrel 208 c may beundergoing cutoff wavelength testing, and a fourth fiber sample wrappedaround mandrel 208 d may be undergoing glass measurement testing.

As shown in FIG. 12A, the fiber deflection and coating geometry teststation 110 includes a fiber clip 300 attached to a deployment slide302, a cutting device 304, a fiber discarding device 306, and a coatinggeometry tester 308. An optical fiber deflection tester 310 includes aspin drive 312. The test station 110 also includes an RF tagidentification read device 318 and an RF tag identification write device320. Operation of the test station 110, including one or more computers316, is controlled by a local PLC 314. According to a preferredembodiment of the present invention, two samples from each spool areprocessed simultaneously.

FIG. 12B shows a method 350 for automating the performance of the fibercurl and coating geometry tests utilizing the test station 110 shown inFIG. 12A. In first step 351, the RF tag reading device 318 reads the RFidentification tag 52, determining routing instructions and processinginstructions for the spool 10. In a second step 352, the local PLC 314determines if the routing instructions indicate that the spool 10 shouldbe processed by the test station 110. If the local PLC 314 determinesthat the spool 10 is not to be processed by the test station 110, thepallet 50 or 90 is moved to the next test station in step 353. If thelocal PLC 314 determines the spool 10 is to be processed by the teststation 110, the pallet 50 or 90 is moved into position adjacent to theslide 302 in step 354, as shown in FIG. 12A. The fiber clip 300 is movedby the deployment slide 302 toward the spool 10 where the clip 300engages and holds the fiber end 12 a. The deployment slide 302 moves theclip 300 away from the pallet 50 or 90, deploying a length (e.g., 8inches) of the optical fiber. In step 355, the cutting device 304 cutsthe optical fiber, leaving a sample of the optical fiber held by theclip 300. In step 356, the fiber clip 300 moves along the slide 302 andpasses the optical fiber sample to the spin drive 312 which holds thefiber sample by an end.

Next, in step 358, the PLC 314 commands the computer 316 to run thefiber curl tester 310. The optical fiber sample is rotated about itsaxis by the spin drive 312 while measurements of deflection versus areference are periodically taken. From this data, a measurement of fibercurl is determined. In step 360, the clip 300 reacquires the sample fromthe spin drive 312 and slides the sample along the slide 302 to thecoating geometry tester 308. In step 362, the fiber sample passes to aclamp or fiber gripping device which then rotates the sample of opticalfiber into a vertical orientation and inserts it into the coatinggeometry tester 308. The PLC 314 commands the computer 316 to run thecoating geometry tester 308. In this test, the fiber sample is placedvertically and rotated about its axis by the coating geometry tester 308while data relative to coating and glass fiber geometry is measured.From this data, various parameters about the placement of the fiberwithin the coating are determined. Next, in step 364, the fiber sampleis removed from the coating geometry tester 308 by the clamp and passedto the clip 300. The clip 300 moves the sample along the deploymentslide 302 to the fiber discarding device 306 which acquires and discardsthe fiber sample. In step 366, the RF tag writing device 320 writes theresults of coating geometry and fiber deflection tests to the RFidentification tag 52. The conveyor 118 then transports the pallet 50 or90 to the next test station.

As shown in FIG. 13A, the PMD test station 112 includes a fiber clip 400and a gripper 401 attached to a deployment slide 402, a cutting device404, and a PMD tester 408. A V-groove tool 410 with clips 414 is locatedadjacent to the deployment slide 402. The test station 112 also includesa transfer slide 412 with fiber clips 413. Stripping devices 416,cleaning devices 418, cleaving devices 420 are located adjacent to thetransfer slide 412. The PMD tester 408 includes clips 421. The teststation 112 also includes an RF tag identification reading device 424and an RF tag identification writing device 426. Operation of the teststation 112, including one or more computers 428, is controlled by alocal PLC 430.

One exemplary type of PMD tester suitable for use with the presentinvention is described in U.S. Provisional Patent Application Ser. No.60/127,107, filed on Mar. 31, 1999, entitled “System and Method forMeasuring Polarization Mode Dispersion Suitable for a ProductionEnvironment” which is incorporated by reference herein in its entirety.

FIGS. 13B and 13C show a method 450 for automating the performance ofthe fiber PMD test utilizing the test station 112 shown in FIG. 13A. Ina first step 451, the RF tag read device 424 reads the RF identificationtag 52, determining routing instructions and processing instructions forthe spool 10. In a second step 452, the local PLC 430 determines if therouting instructions indicate the spool 10 should be processed by thetest station 112. If the local PLC 430 determines that the spool 10 isnot to be processed by the test station 112, the pallet 50 or 90 ismoved to the next station in a step 453. If the local PLC 430 determinesthe spool 10 is to be processed by the test station 112, the pallet 50or 90 is moved into position adjacent to the slide 402 in step 454, asshown in FIG. 13A. The fiber clip 400 is moved by the slide 402 towardthe spool 10 where the clip 400 engages and holds the fiber end 12 a andthe deployment slide 402 moves the clip 400 away from the pallet 50 or90, deploying a length (e.g., 12 inches) of the optical fiber 12 abovethe V-groove of the V-groove tool 410. In step 455, the clips 414 of theV-groove tool 410 elevate and acquire the optical fiber as the clip 400releases it. In step 456, the cutting device 404 cuts the optical fiber,leaving a sample of the optical fiber held by the clips 414. In step457, the clips 414 lower the optical fiber sample to the bottom of theV-groove and the clip 414 closest to the conveyor 118 is released. Alsoin the step 457, air is forced through holes in the bottom of theV-groove, creating a bed of air which will allow the optical fibersample to use its own torsional flex to unwind to an untwisted state. Instep 458, the felt-tipped gripper 401 attached to the slide 402 lowersand clamps the fiber sample at the end held by the clip 414. The gripper401 then moves along the length of the sample to straighten it. The clip414 which had previously released the optical fiber sample in the step457 reacquires the sample.

Next, in step 459, the clips 413 move along slide 412 to the V-grooveand acquire the fiber sample from the clips 414. After acquiring thesample, the clips move slightly towards each other, allowing a smallamount of sag to develop in the optical fiber sample. In step 460, theclips 413 move the sample along the slide 412 where the ends of theoptical fiber sample are stripped by stripping devices 416, cleaned bythe cleaning devices 418, and cleaved by the cleaving devices 420. Instep 461, the clips 413 move along slide 412 and pass the sample to theclips 421 of the PMD tester 408 which tests the optical fiber sample. Instep 464, the sample of optical fiber is discarded by the discardingdevice 406. In step 466, the RF tag writing device 426 writes theresults of PMD test to the RF identification tag 52. The conveyor 118then transports the pallet 50 or 90 to the next station.

At the visual inspection station 114 shown in FIG. 8, an operatormanually inspects the spool 10 at the visual inspection station 114. Thelocal PLC 121 routes the pallet 50 or 90 to the inspection station 114after the spool 10 has passed all of the tests described above. Inaddition to inspecting the spool 10, the operator tapes the opticalfiber ends 12 a, 12 b to the spool 10. When the pallet 50 or 90 leavesthe visual inspection station 114, an RF tag reading device 115 readsthe RF identification 52 and transmits the test results to themanufacturing line, allowing the manufacturing process to be adjustedwith timely feedback from the system 100. The conveyor 118 thetransports the pallet 50 or 90 to the unload station 116.

As shown in FIG. 14, the unload station 116 includes an unload device500, a reject queue 502, a rework queue 504, and a passed queue 506. Thelocal PLC 121 routes the pallet 50 or 90 to the unload station 116 afterthe spool 10 has been manually inspected or has failed one of the testsdescribed above. When the pallet 50 or 90 reaches the station 116, thePLC 121 directs the unload device 500 to remove the spool 10 from thepallet 50 or 90 and place the spool in the appropriate queue. The emptypallet 50 or 90 then proceeds to the load station where another spool isloaded.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit and scope of the present invention.Thus, it is intended that the present invention cover the modificationsand variations of this invention provided they come within the scope ofthe appended claims and their equivalents.

1. A system for automating the testing of optical fiber comprising: at least one automated test station adapted to guide a first end of the optical fiber which is stored on a storage spool to a first testing device and perform a test on the optical fiber; and an automated conveyor system adapted to transport the optical fiber storage spool to the test station.
 2. The system of claim 1 wherein said at least one test station is further adapted to: strip a coating from the first end of the optical fiber.
 3. The system of claim 2 wherein said at least one test station is further adapted to: strip the coating from a second end of the optical fiber; and guide the second end of the optical fiber to the first testing device.
 4. The system of claim 2 wherein said at least one test station is further adapted to: cleave the first end of the optical fiber.
 5. The system of claim 4 wherein said at least one test station is further adapted to: clean the first end of the optical fiber.
 6. The system of claim 4 wherein said at least one test station is further adapted to: acquire a sample length of the optical fiber; and perform the test on the sample length of the optical fiber.
 7. A system for automating the testing of optical fiber comprising: a spool upon which the optical fiber is wound; a first station adapted to automatically: strip a coating from a first end and a second end of the optical fiber; cut the first end and the second end of the optical fiber; a second station which includes a first testing device, one of said first or second stations adapted to: guide the first end and the second end of the optical fiber to the first testing device; perform a first test on the optical fiber; and an automated conveyor system adapted to transport the spool from the first station to the second station.
 8. The system of claim 7 wherein: the first station is further adapted to clean the first end and the second end of the optical fiber; and the second station is further adapted to cleave the first end and the second end of the optical fiber.
 9. The system of claim 7 wherein the second station is further adapted to: pull the first end and the second end of the optical fiber; cut a first length of optical fiber from the first end; cut a second length of optical fiber from the second end; and discard the first length and the second length.
 10. The system of claim 7 wherein: the first test comprises determining a measurement of the optical attenuation of the optical fiber using optical time domain reflectometry.
 11. The system of claim 7 wherein: the first test comprises determining a measurement of the optical dispersion of the optical fiber.
 12. The system of claim 7 further comprising: a pallet for carrying the spool; a radio frequency (RF) tag attached to the pallet adapted for containing data, the data including spool identification data, test processing instructions, and test results; and a plurality of RF tag devices located adjacent to the automated conveyor system adapted to read data from and write data to the RF tag.
 13. The system of claim 7 further comprising: a third station adapted to: acquire a test sample length of the optical fiber; guide the test sample length of the optical fiber to a second testing device; and perform a second test on the test sample length of optical the optical fiber; wherein the automated conveyor system is further adapted to transport the spool from the second test station to the third test station.
 14. A system for automating the testing optical fiber, the optical fiber including a first end and a second end, the system comprising: a spool upon which the optical fiber is wound; a first test station, the first test station adapted to: manipulate the first end and the second end of the optical fiber; guide the first end of the optical fiber to a first testing device; perform a first test on the optical fiber; a second test station, the second test station adapted to: acquire a test sample length of the optical fiber; guide the test sample length to a second testing device; perform a second test on the test sample length of optical fiber; and an automated conveyor system adapted to transport the spool from the first test station to the second test station.
 15. A method for automating the testing of optical fiber comprising the steps of: transporting an optical fiber storage spool which stores a length of optical fiber to a first test station by an automated transportation system; acquiring a sample length of the optical fiber from the spool by a testing apparatus; guiding the sample length of the optical fiber to an optical fiber tester by the testing apparatus; and testing the sample length of the optical fiber by the optical fiber tester.
 16. The method of claim 15, after the step of acquiring a sample length, further comprising the steps of: stripping the coating from at least one end of the sample length of optical fiber by the testing apparatus; cleaving the at least one end of the sample length of the optical fiber by the testing apparatus; and cleaning the at least one end of the sample length of the optical fiber by the testing apparatus.
 17. The method of claim 15, after the step of testing the sample length, further comprising the step of: discarding the sample length of the optical fiber.
 18. The method of claim 15, further comprising, after said testing step, transporting said fiber spool to a second test station.
 19. A method of testing a spool of optical fiber: placing the spool of optical fiber onto a pallet such that a first end and a second end of the optical fiber extend outward in such a manner as to provide easy access to both the first end and the second end; transporting the pallet to a test station; pulling the first end of the optical fiber to a test device such that a first length of optical fiber is unwound from the spool; pulling the second end of the optical fiber to the test device such that a second length of optical fiber is unwound from the spool; and testing the optical fiber wound onto the spool.
 20. The method of claim 19 wherein: the step of pulling the first end of the optical fiber does not disturb the second end of the optical fiber.
 21. The method of claim 19 wherein: the step of pulling the second end of the optical fiber does not disturb the first end of the optical fiber.
 22. The method of claim 19 further comprising the steps of: cutting a portion of the first length of optical fiber pulled from the spool; and cutting a portion of the second length of optical fiber pulled from the spool.
 23. A method of testing a spool of optical fiber: placing the spool of optical fiber onto a pallet such that a first end of the optical fiber extends outward in such a manner as to provide easy access to the first end; transporting the pallet to a test station; pulling the first end of the optical fiber to a test device such that a first length of optical fiber is unwound from the spool; cutting a sample length of the first end of the optical fiber; guiding the sample length of optical fiber to a test device; and performing a test on the sample length of optical fiber. 